1. Field of the Invention
The present invention relates to an electronic printing system which generates the page images prior to printing and, more particularly, to an electronic printing system which determines the complexity of a page prior to attempting to print the page.
2. Description of the Related Art
Electronic printing systems rasterize, or generate in digital form, page images prior to transfer to an image output terminal for printing. The rasterization process can be performed in any of a variety of different manners. One rasterization process, for example, comprises the decompression of a simple image received from an associated scanner. A more complicated rasterization process comprises rasterization of some intermediate format generally associated with receipt of image information from a networked work station. For compactness, the intermediate format contains commands describing the line segments, curves, characteristics, images, etc. which must be combined to create a desired page image. Electronic printing systems rasterize the intermediate format prior to printing. This rasterization is commonly performed in real-time as the page image is transferred for a processing operation.
The time required to rasterize a page image is directly related to the complexity of the page image, i.e., the quantity, size and type of objects comprising the page. In some cases, the time required to generate a complex page exceeds the real-time capability of the subsystem which normally performs the real-time rasterization. Such electronic printing systems will detect this condition, abort the page being printed and raise an error message at a display to the user. Recovery methods must then be performed which vary according to the printing system used. At minimum, the user must then remove and discard the aborted page. Alternatively, some electronic printing systems allow the user to select a different operating mode which redirects other system resources to the imaging task.
U.S. Pat. No. 4,896,275 to Jackson discloses a method of converting complex graphics and picture images in binary form into bit map representations which include only image data that is essential for image reproduction by an output printer with limited buffer memory. A block of data is stored at a time in an input buffer, the data being analyzed one byte at a time. Based on the analysis, bit map representations are generated describing only essential data. The essential data contained in the generated bit map representations is transferred to an output buffer along with generated horizontal and vertical positioning information and other parameter information required to reproduce the bit map representation.
The related art thus compensates for memory limitations in an electronic printing system by generating representations including only essential image data. The related art does not address the problems associated with real-time rasterization of complex pages.